A resolution of the puzzle of low Vus values from inclusive flavor-breaking sum rule analyses of hadronic τ decay data

Continuum and lattice methods are used to investigate systematic issues in the sum rule determination of Vus using inclusive hadronic τ decay data. Results for Vus employing assumptions for D>4 OPE contributions used in previous conventional implementations of this approach are shown to display unphysical dependence on the sum rule weight, w, and choice of upper limit, s0, of the relevant experimental spectral integrals. Continuum and lattice results suggest a new implementation of the sum rule approach with not just ｜Vus｜, but also D>4 effective condensates fit to data. Lattice results are also shown to provide a quantitative assessment of truncation uncertainties for the slowly converging D=2 OPE series. The new sum rule implementation yields ｜Vus｜ results free of unphysical s0- and w-dependences and ～0.002 0 higher than that obtained using the conventional implementation. With preliminary new experimental results for the Kπ branching fraction, the resulting ｜Vus｜ is in excellent agreement with that based on Kl3, and compatible within errors with expectations from three-family unitarity.